Ocular trocar assembly

1. A trocar assembly for delivering a payload into tissue, comprising:

a primary housing;

a cannula defining a lumen and having a proximal portion received in the housing and a distal portion extending from the housing;

a payload disposed in an initial position within the housing and in communication with the cannula;

an actuator for advancing the payload through the lumen to exit via the distal portion of the cannula;

a trocar comprising a distal end with a tip for piercing tissue and a proximal end in communication with a shifter for positioning the trocar, wherein, in an extended position, the trocar occupies the lumen and extends past the distal end of the cannula, and, in a retracted position, the trocar is sufficiently retracted from the lumen such that the payload can pass through the lumen to exit via the distal end of the cannula.

2. The assembly of claim 1 , wherein the trocar is non-coring.

3. The assembly of claim 1 , wherein the trocar comprises metal.

4. The assembly of claim 3 , wherein the trocar comprises stainless steel.

5. The assembly of claim 1 , wherein the shifter comprises a trigger mechanism capable of being activated by a user for extending and retracting the trocar.

6. The assembly of claim 1 , further comprising a lock for locking the trocar in the retracted position.

7. The assembly of claim 1 , wherein the payload comprises a liquid.

8. The assembly of claim 1 , wherein the payload comprises a gas.

9. The assembly of claim 1 , wherein the payload comprises a solid.

10. The assembly of claim 1 , wherein the distal end of the cannula is coupled to the housing.

11. The assembly of claim 1 , wherein the payload comprises a pharmaceutical agent.

12. The assembly of claim 1 , wherein the diameter of the trocar is between 0.20 mm and 0.75 mm.

13. The assembly of claim 12 , wherein the diameter of the trocar is approximately 0.5 mm.

14. The assembly of claim 1 , wherein the trocar creates a channel from about 16- to about 32-gauge in the tissue.

15. The assembly of claim 14 , wherein the trocar creates a 25-gauge channel in the tissue.

16. The assembly of claim 1 , wherein the cannula comprises metal.

17. The assembly of claim 16 , wherein the cannula comprises stainless steel.

18. The assembly of claim 1 , wherein the cannula comprises a polymeric material.

19. The assembly of claim 18 , wherein the cannula comprises polyimide and/or polycarbonate.

20. The assembly of claim 1 , wherein the payload resides in a payload receptacle in the housing.

21. The assembly of claim 20 wherein the payload receptacle is can be detached from the housing.

22. The assembly of claim 21 , wherein the payload receptacle is a cartridge or ampoule.

23. The assembly of claim 22 , wherein the payload receptacle is any of a single use, refillable and sterilizable.

24. The assembly of claim 1 , wherein the tissue comprises an eye.

25. A method for delivering a payload to a tissue comprising:

placing the distal end of the cannula of the trocar assembly of claim 1 in contact with or adjacent to the tissue;

inserting the trocar, in the extended position, into the tissue;

retracting the trocar to the retracted position;

advancing the payload through the lumen and depositing the payload in the tissue; and

removing the cannula from the tissue.

26. The method of claim 25 , wherein the trocar is shifted to the extended position from the retracted position prior to insertion into the tissue.

27. The method of claim 25 , wherein the trocar occupies the lumen and extends past the distal end of the cannula in the extended position prior to insertion into the tissue.

28. The method of claim 25 , wherein when the trocar is retracted, the distal end of the cannula remains within the tissue.

29. The method of claim 25 , wherein the payload is advanced by any of a plunger, pump, vibration or electrostatic gradient.

30. The method of claim 29 , wherein the payload is advanced by a plunger and the plunger is activated by any of a spring, compressed gas, or manual compression.